Roasting and oxidizing furnace.



No. 634,247. Patented oct. 3, |899.

A. BOPP. BOASTING AND DXIDIZiNG FUBNACE.

(pialicaton led Septf 28, 1898.)

(No Model.) 3 Sheets-Sheet 1 nu: Noms me@ no, mum-uwe.. wAsmNsToN. n. c.

N0. 634,247. Patented oct. 3, |899."

. A.noPP.

ROASTING AND OXIDIZING' FURNACE.

(Application led Sept, 2B, 1896.) No Model.) 3 Sheets-Sheet 2,

TN: Nonms 'persas co., PHnToMTNm. wAsmNmnu. n. cA K UNiTED STATE."

PATENT Erica.

ALFRED BOPP, OF SELBY, CALIFORNIA.

RoAsT'lNc AND oxlolzlNe FURNACE.

SPECIFICATION forming part of Letters Patent No. 634,247, dated October 3, 1899.

Application 'died september 28,1896. semi No. 607,158. m0 model.)

To a/ZZ whom it may concern:

Be it known that I, ALFRED BOPP, a citizen of the United States, residing at Selby, in the county of Contra Costa, Stateof California, have invented certain 'newY and useful Improvements in Roasting and Oxidizing Furnaces for Mineral Ores, of which the efollowing is a specification.

My invention relates'to furnaces wherein the material being treated is mechanically stirred and gradually moved forward,'as the roasting and oxidizing process proceeds, by means of continuously-moving rakes or rabbles mounted on metallic rope and 'mechanically impelled.

My improvements consist in a modification and extension of Letters Patent of the United States No. 532,013, granted to me January 1, 1895, for an improvement in roasting-furnaces and include the separation of such furnaces in sections or elements, with independent feed and discharge ways, so the furnace can be operated in sections when the ore under treatment does not requirelong exposure to the heat and may pass through a corresponding shorter distance, the mechanical stirring elements and some others being common to.

all the sections.

My invention further consists of an improvement in the guiding-ways of the rabble cars or trucks; also, of the trucks themselves and of the furnace proper, to permit free expansion and contraction of the same; also, in other constructive and operative features, that will` be more fully pointed out and explained in connection with the drawings herewith and in the claims at the end of this speciication.

The objects of my invention are to secure a more rapid and complete Workin g of such furnaces, reducing the cost of their maintenance, and to increase their durability in service.

Referring to lthe accompanying drawings,.

lcenter of one of the sections of a furnace shown in Fig. 3. Fig. 5 is a partial elevation of Fig. 3, showing various parts iu side view. Fig. 6 is a side View of one of the cars or trucks on which the stirring-rakes or rabbles are mounted. Fig. 7 is a detail of Fig. 6, showing the manner of swiveling the axes of the car or truck Wheels. Fig. 8 is a partial crosssection through one of the furnaces, showing 4the method of connecting the hearths so as to provide for expansion and contraction. Fig. 9 is a plan view, partially in section, of the parts shown in Fig. 8. Fig. 10 is a broken view of the metallic bars forming connection between the ends of the furnace-walls. Fig. 11 is a broken section through the furnace-top, showing the devices to provide for expansion and contraction thereof. Fig. 12 is a diagram indicating the path of the trucks around the impelling-Wheels.

Similar numerals and letters of reference are employed to denote like parts throughout the different figures of the drawings.

The treatment of ores called roasting involvesthe exposure of various operative parts to the intense heat of the furnace and demands the protection of such partsy by all possible means from distortion or destruction. In the mechanical method of operating such furnaces, to which my invention pertains, the stirring devices have to be cooled at intervals after a certain period of exposure to the heat, the metallic structural elements of the lfurnace have to expand and contract with the Variations of temperature witho ut in j uriously disturbing the masonry and refractory linings, conduits or chambers of any kind communicating with the furnaces should open upward, so the intense heat will not descend and penetrate such openings and injure the apparatus therein, such precautions being necessary to insure durability of the various parts and avoid the expense and delay of derangement. To this end Ir provide the various improvements nowto be described, first referring to Fig. 1, which represents in plan a common roasting-furnace embodying my improvements.

A furnace of the class to which my improvements relate is a long inclosed hearth 1, provided with fire-boxes or'heating-fu'rnaces 2 at intervals, the number depending upon the length of the furnace, also on whether the furnace is operated continuously or in sections. The heat from the fire-box 2 passes over bridge-walls 3 and then longitudinally over the roasting-hearth proper, as seen in Fig. 2, finally passing to the chimneys 16.

To expose the ore to uniform treatment or roasting, it is called, itis necessary that it be stirred and moved toward the end of the furnace where it is discharged, the length of the hearths and also the rate of longitudinal movement determining the time of treatment or exposure of the ore to the heat.

In Fig. 1 the furnace is single in respect to all of its operative elements-that is, the ore traverses the whole length of the furnace, being fed in continually from the top, as shown at 5 in Fig. 5, and is moved forward toward the discharge end, where it falls down into the cars G through chutes 7,-as seen in Figs. 1, 3, and 5.

Referring next to the stirring devices, these consist of the endless double ways S, that pass through a conduit 0 in the bottom of the furnace, so placed because the heat and gases of combustion, having a tendency to rise, do not penetrate the cond uit in such degree as to destroy the operative parts therein. On these ways S are placed a series of trucks or cars lO, connected by an endless cable 1l, that passes around the wheels or pulleys 2, one at each end ol'l the furnace. One or both of these wheels or pulleys 12 are driven by some suitable power, so as to cause a continuous movement of the trucks 10 through the conduit f) and reversely outside the furnace in the open air, as seen in Figs. 1 and This distance traversed in the open air being about one and one-half times as long as the length of the conduit t), the various parts are cooled on their return movement, and will thus resist the heat of the furnace during the time of stirring and moving the ore. Mounted on these trucks 10 are rakes or rabbles 13, consisting of a braced cross-bar 1iE and oblique blades or teeth 15, that stir and move forward the ore on the hearth 1, in the manner as set forth in my Letters Patent No. 532,013, hereinbefore referred to.

The cars or trucks 10, being subject to varions strains, laterally and otherwise, because of the rakes 13 and the resistance in stirring, also in passing around wheels 12, to secure endurance and perfect action, require various provisions not at first ascertained.

The axles 17 I pivot at 44, as seen in Fig. 7, so as to compensate in rounding the curves at the pulleys 12. I also provide side bearing rollers or wheels 1S, both behind and in front of the bearing-wheels 19, that guide the trucks and resist lateral strain, also guide the trucks in passing the curves, as will be presently explained.

The ways or track S is not arranged tangent to the wheels or pulleys 12, but has reverse curves 20, as indicated by the radii a in Fig. 1. This is an important and necessary provision when the impelling-cable is attached at 2l in the center of the trucks l0, as seen in Figs. l and (i.

If the ways 8 were tangent to the pulleys or wheels 12, then the forward wheels lf) of the trucks 10 would enter the curve before the cable 11 had entered upon the wheels 12 and the cable would be deflected inward from its true course, so that when it came in contact with the wheels I2 the trucks 10 would be crowded outward laterally and be derailed, strained, or broken, but by introducing the reverse curves at 2O the cable 11 follows a nearly straight line when entering upon and in leaving the wheels 12 almost tangentially, the same as if free and without attachment to the trucks 10. This modification of the ways S can be better explained by referring to the diagram Fig. 12, where a is the path of the point of attachment of the cable 21 to the trucks 10; also represents the circumference of the pulleys 12. e is the point of attachment of the cable 11 at 21. d are positions of the truck-wheels. The curve b is in the center of the ways 8. Upon entering this curve Z) the forward wheels ofthe trucks are diverged outward by the reverse curves 20, and the center of attachment for the cable e is moved outward, as seen at m, a distance equal to one-half of the chord n. This does no harm, and as soon as the rear wheels of the truck 10 enter the curve I) then the difference between the radius of the curves d and b is the chord n. The same occurs when the trucks leave the curve b and enter on the line f at the other sides of the wheels 12. The cable 11 is attached at 2l to the plates 22, on which the rabble 13 is supported, provision being made at some portion of its length to take up the slack due to wear and stretching.

The plates or webs 22, on which the rabbles 13 are supported, are made of a thin section, so as lo move in the slot 23, which latter is made as narrow as possible to protect the couduit 9 and the trucks l0 from the heat of the furnace and to prevent the ore from falling in. To prevent a rubbing friction at the sides of the slot 23, I place rollers 25 at the front and rear of this plate 22, to bear on the side plates 2G, as the deviations of the rabble 13 may require.

To prevent the escape of heat at the end of the main furnaces when the rabbles 13 pass out and in, I provide swinging trap-doors 21. (Seen in section, Figs. 1, 2, 3, and 4.) These trap-doors 24 can be single plates to span one-half of the furnaces width, as seen in Fig. 2, or can be further divided so as to open and close in sections, as the diagonal braces 2S on the rabbles 13 permit, or to prevent shock by the falling of such sections iingers or guards 29 (seen in Fig. (i) can be provided, so the doors 24 can slide down on these and close gradually. This detail of the furnace can be arranged in various ways constructively, so as to close the path of the rabbles 13 after they have passed.

I have indi- IOD cated methods that have operated well in practice.

It is evident that in furnaces of the present kind, often exceeding one hundred feet in length and subject to a high degree of heat on the inside and in the principal members, continuous rigid construction is not possible and that provision for expansion and contraction must be made. This I provide for by dividing the continuous or single form of my improved furnace into divisions, as from A to B in Fig. l. Interposed between these sections and forming a continuation of the main side wallsSl I employ metal channel-bars 30 of two dimensions, as shown in section Figs. 8 and 9 and in side View at Fig. l0. These bars 30 are made to slide one within the other, but overlapping, so as to give lateral stability to the walls 3l. At the ends of the furnace I employ, preferably, bars 32 of stiff section, connected by longitudinal through-bolts or rods 33 to channelbars 30 in the usual manner. This permits each division of the furnace-Walls to expand or contract independently, the channel-bars 30 sliding one within the other, as seen in Fig. 9.

The transverse bracing of the furnace, consisting of the side bars 34 and tie-rods 35, (seen in Figs. 2 and 5,) is of the usual con struction and doesnot require description.

Similar provision for expansion and contraction has to be made for the various elements or parts of the furnace subjected to heat. Y

The hearths l are arranged with aspace between at each division of the furnace, as indicated by the dottedlines 37 in Fig. 9. This space 37is covered by aplate 38, having angular ends 39, bolted at one end to the outer or larger of the channel-bars 30 and at the other orinner ends to one of the plates 26, so that in expansion and con traction this plate 38 slides on the hearth l at one side and maintains a close joint at the bot-tom under the fettling and ore. The'space 37 extending from the ground to the top of the furnace, as, shown in Fig. l0, the top 4 of the furnace has also to be provided with means to permit expansion the same as the hearth, (shown in Figs. 8 and 9,) a plate 45 being bolted to outer channelbars 30 at each end, as shown at 46 in Figs. 2, S, 9, l0, and ll, allowing this plate 45 to slide on the top or arch 4 in the same manner as plate 38 slides upon the hearth l to close the aperture 37,thus preventing the escape of the gases and heat.

Referring now to the sectional form of my improved furnaces, (illustrated in Figs. 3 and 4, Fig. 5 being an elevation,)'the preceding description applies to the various parts, except that the furnace is divided into sections, or it may be said several furnaces are set in line, all served by the same stiriing and operating mechanism, each section or furnace 40 having feeding-inlets 42 and supply-cars 4l, as shown in Fig. 5 and indicated by dotted lines in Fig. 3. At one end of each furnace 40 there are hopper-cars Gf and chutes 7, and ways 43 for the removal of the ore aftertreatment. The object of this division into sections is to attain increased capacity when the sulfur. or other minerals to be oxidized or burned out are small in quantity and do not require a long time for treatment. In this case it will be seen that the several sections 40 are all served by the same stirring mechanism, the rabbles 13 passing from one furnace to the vother the same as if the walls 3l and the hearth l were continuous. It is simply a modification of the construction shown in Figs. l and 2, With feeding and discharging devices for each section 40.

Having thusexplained and described my improvements in roasting-furnaces, with the nature and objects of my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In an ore-roasting furnace, an elongated furnace-chamber provided with a roastinghearth and conduit beneath; a series of rakes or rabbles connected by an endless rope, located in the conduit, and impelled by wheels or pulleys at the ends of t-he furnace, said rakes or rabbles being supported and guided by cars or trucks mounted on'ways beneath and outside the furnace, each of said Ways having a double or reverse curve and increased radius around the wheels or pulleys, so that the impelling-rope will enter upon and.l leave the guiding and driving pulleys Without lateral strain.

2. In an orc-roasting furnace,a main hearth and tire-boxes communicating therewith; a series of m echanically-impelled rakes or rabbles to stir and move the ore, rails or waysin a conduit beneath the hearth of the furnace and extending beyond the ends thereof and having reverse curves in the extended portions, and cars or trucks carrying the rakes or rabbles, the car or truck Wheels being provided witli swiveling axles to accommodate the curves at the ends of the furnace.

3. In an ore-roasting furnace, a hearth, reverberatory top and side Walls, said hearth, reverberatory top and side walls being divided into separate sections, each of which is braced by through rods or bolts and metallic bars 30 that will telescope or slide one upon the other, permitting longitudinal expansion and contraction ot the walls ofeach section.

4. In an ore-roasting furnace, a hearth, reverberatory top and side Walls in divisions, and plates 30, 3S and 45, to cover the spaces between the divisions of the hearth, side walls and top, said plates being attached to one division of the furnace and adapted to slide on the other division,whereby the heart-h, top and side walls may expand and contract together.

5. A plurality of separate, ore-roasting furnaces, each provided with doors at its ends, said furnaces being arranged in alinement ICO mechanism operated by the carrier; and supports at the ends of the plurality of furnaces and at suitable intermediate points for supporting said carrier.

In testimony whereof I have hereunto afxed my signature in the presence of two witnesses.

ALFRED ROPP.

\Vitnosses:

THos. RICKARD, B. T. LACY. 

